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I use Thunderbird to send email. My mail server inserts my IP address into the header of my emails. Is there a way to hide this? I’ve thought of sending my mail to the server through Tor but my server apparently refuses tor connections.

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  • Have you tried any add-on to change the header? I found two with a simple Google search – Ulkoma Feb 12 '15 at 19:55
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    @Ulkoma, most mail servers will always include the client's IP address in the Received: header, which is appended after the client hands the mail to the server. Client add-ons cannot affect that. – gowenfawr Feb 12 '15 at 19:56
  • Tried that. I can insert add-ons but not remove my IP address. – piper1935 Feb 13 '15 at 0:07
  • What's obvious to me, but may not be to some who have had less net training, is that the receiving E-Mail server will know the IP address of the system that contacts it. This is absolutely required because SMTP uses TCP and TCP doesn't send significant data until after a "3-way handshake" process (outgoing, incoming, outgoing) is completed. So the system receiving the SMTP connection must reply, and that is needed before the SMTP's HELO gets processed. So the receiving E-Mail server will know the IP address. If you use e.g. Tor, the receiving server knows the IP address of a Tor computer. – TOOGAM Feb 17 '15 at 5:43
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Some mail providers, such as Hushmail, strip all IP information from mail before forwarding along. But this is, in general, only a service provided by secure or anonymous email services, not something you can make your existing provider do.

Because the IP addresses in the "Received" headers are stamped on by the mail servers, it's not possible for clients to remove them - you need a complicit mail server working to keep your IP out of the record.

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  • Also to mention riseup. – sebix Feb 12 '15 at 20:26
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The IP information is added by the mail server. There is nothing you can do to stop this at the client end when sending your email if you are using a reputable mail server. Once upon a time, mail servers were very trusting and often misconfigured and you could get away with things to a greater extent. Thanks to spammers and the risk of mail servers being put into spamming blackholes so that other mail servers will not accept mail from them, things have changed and there is little trust.

You could run your own mail server and have it relay to your ISP server (if your ISP will allow this). This would allow you to fake some of the information and your mail server IP would be in the headers, but your ISP might not inject your client IP address, but this is a fair bit of work and a long shot. Easier just to get a hushmail account!

The only way to reliably achieve what you want is to use a mail service, such as hushmail, which specifically provides a service designed to hide/anonamise sender information.

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  • I wish my mail server animalized my corrospondence. – Sam Axe Feb 16 '15 at 11:56
  • Running your own mail server won't fix the problem - the best you would be able to do would be to obfusicate the address by adding other fake addresses before it in the chain. – davidgo Feb 17 '15 at 4:28
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According to RFC 821 e-mail client should send its domain name in the Helo/EHLO command. So the answer is yes, Thunderbird sends out the IP in e-mail headers.

But this behaviour is reversible, just create mail.smtpserver.default.hello_argument parameter with a example.com string value via Thinderbird's Config Editor (Preferences > Advanced > General). You can assign anything instead of example.com, of course.

Need to be noted, that this is actually will not conceal your IP from mail server, this trick just removes that info from the header. For real anonymity, you should use some kind of anonymization software, such as Tor.

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  • You seem to be flipping from "domain name" to "IP". Is this intentional? – schroeder Feb 12 '15 at 22:27
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    Consider the following standard header: Received: from mail-vc0-f182.google.com (mail-vc0-f182.google.com [209.85.220.182]) by li1-23.members.linode.com (Postfix) with ESMTPS id 24DF04800. The first name ("from mail-vc0...") was how the client identified itself (via HELO/EHLO). The bit in parentheses is where the mail server both logged the IP address and did a reverse DNS lookup so it could log what the name really was, not just what the client said it was. So you can muck with HELO/EHLO all you want, just be aware that mail servers don't believe a word you say when you do it. – gowenfawr Feb 12 '15 at 23:12
  • I'm not necessarily interested in hiding my IP from the mail server, just from the recipient of the email. – piper1935 Feb 12 '15 at 23:55
  • @user45475 Didn't work for me. The new parameter adds my domain name to the header, which I set as the string value, but doesn't remove my IP address, which is what I want to do – piper1935 Feb 13 '15 at 0:03
  • @schroeder Yes, I believe it was. user45475 seemed to be using the right term in the right places. He was commenting on both. – TOOGAM Feb 17 '15 at 5:40
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TorBirdy is a plugin for Thunderbird. It tries to anonymize your connection and deletes or changes several informations.

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  • Tried that. My mail server refuses tor connections – piper1935 Feb 14 '15 at 20:35
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You could set up a mail server that acted as a relay. Since you would control the relay software, you could use any mail server software that allowed you to strip/anonymize connection info.

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  • at that point the emails become traceable back, not to your client, but to the server you own. And servers usually stay in one place and leave a paper trail. Anonymizing servers work well when they're run by a trusted third party who's obscuring the trails for multiple unrelated parties... not so well when you run your own. – gowenfawr Feb 16 '15 at 13:52
  • @gowenfawr: with the proliferation of vm hosting services like Azure, this becomes much less of a problem. If you think the server has become compromised then just delete the vm and spin up another somewhere else. – Sam Axe Feb 16 '15 at 13:53